Corrected set-custom-cart-item query samples

[nofuss]

Purpose of this pull request

This pull request (PR)

• Corrected cart_item_id argument to use the uid rather than the numeric id.

• Added cart_item custom_attributes field to cart response: previous missing.

Affected pages

• ...

Links to Magento Open Source code

• ...

whatsnew
Corrected examples in the setCustomAttributesOnCartItem mutation.

[github-actions]

🔍 Linter Report

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                     LINTER REPORT
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Generated: 2026-07-16T04:49:05.132Z
Mode: Full Linting (all rules + dead links check)
Target Directory: /home/runner/work/commerce-webapi/commerce-webapi
Skipped Rules:
  - check-frontmatter → src/pages/includes
  - missing-heading → src/pages/includes

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Files to process: 1


═══════════════════════════════════════════════════════════════
                        SUMMARY
═══════════════════════════════════════════════════════════════

  📁 Files processed:    1
  📄 Files with issues:  0
  ❌ Total errors:       0
  ⚠️  Total warnings:     0
  📋 Total issues:       0

Result: ✅ PASSED - All files passed linting successfully!

═══════════════════════════════════════════════════════════════

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This comment was automatically generated by the linter bot.

[github-actions]

🔍 Linter Report

Click to expand full report

═══════════════════════════════════════════════════════════════
                     LINTER REPORT
═══════════════════════════════════════════════════════════════

Generated: 2026-07-16T04:49:26.871Z
Mode: Full Linting (all rules + dead links check)
Target Directory: /home/runner/work/commerce-webapi/commerce-webapi
Skipped Rules:
  - check-frontmatter → src/pages/includes
  - missing-heading → src/pages/includes

───────────────────────────────────────────────────────────────

Files to process: 1


═══════════════════════════════════════════════════════════════
                        SUMMARY
═══════════════════════════════════════════════════════════════

  📁 Files processed:    1
  📄 Files with issues:  0
  ❌ Total errors:       0
  ⚠️  Total warnings:     0
  📋 Total issues:       0

Result: ✅ PASSED - All files passed linting successfully!

═══════════════════════════════════════════════════════════════

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This comment was automatically generated by the linter bot.